[PATCH -fixes] riscv: Do not restrict memory size because of linear mapping on nommu

[PATCH -fixes] riscv: Do not restrict memory size because of linear mapping on nommu

[Alexandre Ghiti]

It makes no sense to restrict physical memory size because of linear
mapping size constraints when there is no linear mapping, so only do
that when mmu is enabled.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/linux-riscv/CAMuHMdW0bnJt5GMRtOZGkTiM7GK4UaLJCDMF_Ouq++fnDKi3_A@mail.gmail.com/
Fixes: 3b6564427aea ("riscv: Fix linear mapping checks for non-contiguous memory regions")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index eb0649a61b4c..1785782c2e55 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -252,7 +252,7 @@ static void __init setup_bootmem(void)
 	 * The size of the linear page mapping may restrict the amount of
 	 * usable RAM.
 	 */
-	if (IS_ENABLED(CONFIG_64BIT)) {
+	if (IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_MMU)) {
 		max_mapped_addr = __pa(PAGE_OFFSET) + KERN_VIRT_SIZE;
 		memblock_cap_memory_range(phys_ram_base,
 					  max_mapped_addr - phys_ram_base);
-- 
2.39.2

Re: [PATCH -fixes] riscv: Do not restrict memory size because of linear mapping on nommu

[Geert Uytterhoeven]

Hi Alex,

On Tue, Aug 27, 2024 at 8:52 AM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
> It makes no sense to restrict physical memory size because of linear
> mapping size constraints when there is no linear mapping, so only do
> that when mmu is enabled.
>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Closes: https://lore.kernel.org/linux-riscv/CAMuHMdW0bnJt5GMRtOZGkTiM7GK4UaLJCDMF_Ouq++fnDKi3_A@mail.gmail.com/
> Fixes: 3b6564427aea ("riscv: Fix linear mapping checks for non-contiguous memory regions")
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Thanks for your patch!
Sorry, I didn't get to test the preview yesterday...

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH -fixes] riscv: Do not restrict memory size because of linear mapping on nommu

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Tue, 27 Aug 2024 08:52:30 +0200 you wrote:
> It makes no sense to restrict physical memory size because of linear
> mapping size constraints when there is no linear mapping, so only do
> that when mmu is enabled.
> 
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Closes: https://lore.kernel.org/linux-riscv/CAMuHMdW0bnJt5GMRtOZGkTiM7GK4UaLJCDMF_Ouq++fnDKi3_A@mail.gmail.com/
> Fixes: 3b6564427aea ("riscv: Fix linear mapping checks for non-contiguous memory regions")
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> 
> [...]

Here is the summary with links:
  - [-fixes] riscv: Do not restrict memory size because of linear mapping on nommu
    https://git.kernel.org/riscv/c/5f771088a2b5

You are awesome, thank you!
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